Rivet gun

ABSTRACT

A rivet gun for use with blind rivets making use of a closedcircuit hydraulic system.

United States Patent [191 LaPointe [54] RIVET GUN [75] Inventor: GabrielM. Lalointe, Worcester,

Mass.

[73] Assignee: Parker Manufacturing Company;

Worcester, Mass,

[22] Filed: July 22, 1971 [2i] Appl. No.: 165,009

52 u.s.c| ....:.....72/s91,72/453 [S 1] int. Cl. ..B21j 15/20 [58] Fieldof Search .;.....72/39l, 453, 114

[56] References Cited UNITED STATES PATENTS 2,365,538 12/1944 Fischer..72/453 Jan. 30, 1973 2,526,956 l0/l950 Kugler ..72/39r 3,082,8983/1963 Bosch ..72/39l 3,254,522 6ll966 Elliott ....72 391 FOREIGNPATENTS 0R APPLICATIONS 550,230 l2/l942 Great Britain ..72/391 PrimaryExaminer-Richard J. l-lerbst Assistant Examiner-Gene P. CrosbyAttorney-Norman S. Blodgett [57] ABSTRACT A rivet gun for use with blindrivets making use of a closed-circuit hydraulic system.

13 Claims, 12 Drawing Figures PATENTEDJAII 30 ms sum 1 or 4 GABRIELM.LAPo/NrE INVENTOR RIVET GUN BACKGROUND OF THE INVENTION In the art ofriveting, it has become common practice to make use of the so-calledblind rivet". This is a rivet which is tubular in nature and consists ofa short tube having a radial flange at one end. A headed mandrel(similar to a common nail) extends through the tube with its head at theend of the tube opposite the flanged end. It is possible to join twosheet metal articles by passing the tubular portion of the rivet throughmatching holes in the metal objects and, while holding the flangetightly against one side of the assemblage, pulling the mandrel. Thehead of the mandrel or nailcauses a flange to be formed on the free endof the tube and this flange is pressed tightly against the other side ofthe assemblage to form a rivet. The strength of the mandrel is such thattremendous forces are developed in forming the rivets and, eventually,the mandrel breaks. The headed end of the mandrel remains in the rivetor may fall out, but takes no part in the function of the rivet as afastener.

In the past, many rivet guns have been developed and, generallyspeaking, they are either commercial or home handyman-type rivet guns.The handyman" rivet gun is usually a mechanical one which makes use oflevers and ratchets to develop the forces in the mandrel. Such guns havebeen limited in the past to small rivets, since the forces that must ,bedeveloped in the mandrel in large rivets are very large and cannot bedeveloped by simple inexpensive mechanical means. A commercial rivet gunhas usually been connected to a source of pressure air. Examples ofthese commercial guns are shown in the U.S. Pat. to Bosch No. 3,082,898,to Fischer U.S. Pat. No. 2,365,538, and EI- liott et al. U.S. Pat. No.3,254,522. In all of these prior art constructions, the primary forcecomes about by the use of a pneumatic motor. The pneumatic motor, inturn, operates a hydraulic piston which, in turn, produces the forcewhich brings about the pulling of the mandrel. Since the average homeworkman does not have pressure air available, he is not able to make useof these hydraulically operated rivet guns and, therefore, cannot uselarge blind rivets. At the same time, even in commercial applicationswhere it is desirable to do a riveting operation in inaccessible areas,the use of the rivet gun is limited by the unavailability of pressurearea in such areas. Furthermore, all of these hydraulically operatedrivet guns are very expensive because they involve rather complexmachined elements. These and other difficulties experienced with theprior art devices have been obviated in a novel manner by the presentinvention.

It is, therefore, an outstanding object of. the invention to I provide arivet gun using hydraulic operation without the necessity of aconnection to an external power source.

Another object of this invention is the provision of a rivet gun ofcompact size capable of producing large forces for use with large blindrivets.

A further object of the present invention is the provision of a blindrivet gun capable of producing large forces by use of a hydraulicsystem.

I It is another object of the instant invention to provide a hydraulicblind rivet gun whose main body element is capable of production by theinjection molding of aluminum or similar metal.

A still further object of the invention is the provision of a rivet gunproducing a force on the mandrel, which force is entirely controllableby the operator.

his a further object of the invention to provide a rivet gun which is inthe shape of a conventional pistol having an elongated barrel extendingat a right angle to a hand grip and having the mandrel-pulling apparatusat the end of the barrel, thus allowing the rivets to be placed indifficuItto-reach places and arranged so that the operator can work fora long period of time without becoming tired.

With these and other objects in view, as will be apparent to thoseskilled in the art, the invention resides in the combination of partsset forth in the specification and covered by the claims appendedhereto.

SUMMARY OF THE INVENTION In general, the invention consists of a rivetgun for usewith a hollow rivet having a mandrel and having a main bodyhaving a hand grip and a barrel. A squeeze lever is hingedly attached tothe main body adjacent the hand grip and a mandrel grip and a rivethandle is mounted on the free end of the barrel. A primary piston systemis carried in the handle and is operable by the trigger. A secondarypiston system is carried in the barrel and connected to the rivet anvil.A reservoir is provided for containing a body of hydraulic fluid and acheck valve is located between the primary piston system and thesecondary piston system.

BRIEF DESCRIPTION OF THE DRAWINGS The character of the invention,however, may be best understood by reference to one of its structuralforms, as illustrated by the accompanying drawings, in which:

FIG. 1 is a perspective view of a rivet gun embodying the'principles ofthe present invention,

FIG. 2 is a side elevational view of the rivet gun,

FIG. 3 is an end elevational view of the gun,

FIG. 4 is an opposite end elevational view of the gun,

FIG. 5 is a plan view of the gun,

FIG. 6 is an opposite side elevational view of the gun,

FIG. 7 is a bottom view of the gun,

FIG. 8 is a sectional view of the gun taken on the line vm-vm of FIG. 3,

FIG. 9 is a sectional view of a portion of the invention taken on theline IX-IX of FIG. 8,

FIG. 10 is a view taken along the line X-X of FIG. 1

FIG. 11 is a sectional view of the invention taken on the line XIXI ofFIG. 8, and

FIG. 12 is a sectional view of the invention taken on the line XII-XIIof FIG. 8.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to FIGS. 1, 2,3, 4, 5, 6, and 7, which best show the general features of theinvention, the rivet gun, indicated generally by the reference numeral10, is shown as having a main body 11 having a hand grip 12 and a barrel13. The squeeze lever 14 is pivotally attached to the main body 11adjacent the hand grip 12. The mandrel grip l5 and a rivet anvil l6 aremounted on the free end of the barrel 13. The barrel actuator 17 ismounted on the side of the barrel 13. Also evident in these figures is alever system 18 connecting the squeeze lever 14 to the interior of thehandle grip 12.

FIG. 8 shows in general the interior construction of the gun. A primarypiston system 19 is carried in the handle 12 and is operable by thesqueeze lever 14. A secondary piston system 21 is carried in the barrel13 and is connected to the rivet anvil 16. A reservoir 22 is provided inthe barrel 13 for containing a body of hydraulic fluid. The reservoir 22is expandable by virtue of the fact that it is provided with a bore 23in which is slidably carried a piston 24. A coil spring 25 lies betweenthe outer end of the bore 23 and the piston 24. The second piston system21 includes a power bore 26 extending longitudinally of the barrel 13.The first piston system 19 includes a pump bore 27 extending at a rightangle to the power bore 26. The bore 23 of the reservoir 22 is alignedwith the power bore 26. The reservoir bore 23 and the power bore 26 areseparated by a substantial space and an imaginary extension of the pumpbore 27 would pass'through that space. As has been stated, the squeezelever 14 is connected to the first piston assembly 19 by a lever system18. The squeezing of the lever toward the hand grip 12 causes a point inthe system to move the first piston system. The squeeze lever 14isprovided with a protuberance 28 extending from the side of the leverfacing the hand grip 12. The protuberance has a pivot pin 29 which movesparallel to the axis of the pump bore 27 when the squeeze lever 14 ismoved toward the handle grip 12. One end of a first link 31 is pivotallyconnected to the squeeze lever 14 by the said pivot pin 29. One end of asecond link 32 is pivotally connected to the handle grip 12 by a pivotpin 33. The first link 31 is formed with an integral bellcrank arm 34.The ends of the links 31 and 32 are connected by a pivot pin 35. Thebellcrank arm 34 extends beyond the pivotal connection 35 between thelinks and engages a pump piston 36 of the first piston system 19. A coilspring 37 which is concentric with the pump piston 36 is operative tobias the pump piston and the bellcrank arm 34 in the downward direction,i.e., the direction to move the squeeze lever '14 away from the handgrip 12.

'The secondary piston system 21 includes the power bore 26 extendinglongitudinally of the barrel 13 and a piston 38 with a piston rod 39extending to the end of the barrel 13 and connected to the rivet anvil16. The anvil has a bore 41 that is parallel to and spaced from thepower bore 26. The rivet anvil 16 is provided with a hardened metal noseor insert 42 in which the bore 41 is formed. Inside the mandrel grip areprovided jaws 43 adapted to grip the mandrel of the pop rivet. They aremaintained in a normally open position by a plunger 44 which is biasedtoward the jaws by a coil spring 45. The large coil spring 46 biases thepiston 38 to the right in its bore 26.

Referring now toFlGS. 9 and 10, the check valve 47 is mounted betweenthe primary piston system 19 and the secondary piston system 21. Morespecifically, it is connected on one side to the upper end of the bore27 and a passage 48 leading to the inner end of the bore 26 from theside of the piston 38 away from the'piston rod 39 and the coil spring46. The check valve is provided with a ball 49 which is spring-biasedtoward a seat leading to a vestibule 51. The vestibule is not onlyconnected in its central part to the top of the bore 27 of the firstpiston system 19, but also is provided at the other end with a seat 52which is connected to a passage 53 leading to the reservoir 22. A ball54 is pressed against the seat 52 to form a check valve by a coil spring55 i which extends between the ball 54 and the ball 49. Generallyspeaking, the ball 49 pulls away from its seat to allow the pressurehydraulic fluid to flow from the bore 27 to the piston 38 when thepiston 36 is moved upwardly, while the ball 54 moves to the right (inFIG. 9) to connect the passage 53 to the bore 27, to allow fluid to besucked from the reservoir 22 into the bore 7 27 when the piston 36 movesdownwardly.

Extending laterally into the barrel 13 above the check valve 47 is abore 56, the inner end of which is connected by a passage 57 to theinner end of the bore 26, while the intermediate portion of the bore isconnected by a passage 58 to the reservoir 22. A plunger 59 is slidablycarried in the bore 56 and is biased outwardly by a coil spring 61. Theinner end of the plunger is provided with a pin 62 which has a conicalend engageable with a seat or end of a small passage 63 leading from thebore 56 to the passage 57. The valve actuator 17 is pivotally mounted onthe barrel 13 by means of a pivot pin 64. At its upper end, it has anadjustable contact screw 65 which engages the outer end of the plunger59, the other end of the valve actuator being resiliently biasedoutwardly by a coil spring 66 extending between the lower end of theactuator and the barrel 13. In other words, the spring 66 keeps thecontact screw 65 pressed against the plunger 59, so that the stem or pin62 of that plunger is maintained against the end of the passage 63 undernormal circumstances.

Referring to FIG. 11, it can be seen that the squeeze lever 14 isprovided with double walls 67 and 68 in which is held the pivot pin 29.The end of the link 31 is centered between the two walls by washers 69and 71. In FIG. 12 it can be seen that the handle 12 is formed of twoplastic elements 72 and 73, outside of which extends sheet metalelements 74 and 75. The elements are held together by the pivot pin 33which is in the nature of a rivet.

The operation of the invention will now be readily understood in view ofthe above description. The blind rivet is mounted on the rivet anvil 16by passing the mandrel through the bore 41, so that it lies between thejaws 43. The flange on the rivet portion rests against the front portionof the nose or insert 42. The operator holds the rivet gun in a mannersimilar to a shooting gun and inserts the rivet through the two elementsthat are to be fastened together. He then squeezes the squeeze lever 14toward the handle 12 and, through the lever system l8,the piston 36 ismoved upwardly in the bore 27. Hydraulic fluid flows up into thevestibule 55 (see FIG. 9) and forces the ball 49 to the right againstspring pressure. Oil is allowed to flow around the ball 49 and into thepassage 48.to the end of the bore 26. The oil.pressure presses thepiston 38 of the secondary piston system to the left carrying the rivetanvil 16 to the left with it. The rivet, including the mandrel, startsto the left, but any slight movement of the mandrel through the jaws 43causes them to grip it even tighter,

so that it is prevented from moving any distance. The

movement of the nose or insert 42 to the left, however, causes the'headon the mandrel to collapse the free end of the hollow rivet on the otherside of the elements which are to be fastened. Upon completion of astroke of the piston 36, the operator allows the squeeze lever 14 tomove back away from the handle grip 12. The coil spring 37 carries thepiston back down again. When it does this, suction is created in thebore 27 above the piston and this closes the ball 49, while, at the sametime, causing the ball 54 to move to the right against the pressure ofthe spring 55. This allows oil to travel from the reservoir 22 throughthe passage 53 around the ball 54 and into the bore 27. Hydraulic fluidis, therefore, available for the next stroke of the piston 36. Theoperator then squeezes the lever 14 toward the handle grip 12, causingthe piston 36 to move upwardly again and introduce a further amount offluid into the bore 26 to the right of the piston 38. Each time thiscycle is repeated, the rivet anvil 16 moves further away from the jaws43 in the barrel 13. This causes the head on the mandrel to continue toform a flange on the back side of the articles to be riveted together.Eventually, the flange is .formed up against the back surface of thesearticles in such a way that further operation of the gun no longerresults in deformation of the rivet, but only serves to increase theforces in the mandrel greatly. Eventually, these forces reach an amountsufficient to break the mandrel in the customary way and the rivetingoperation is completed. The loose teeth of the mandrel lie in thepassage through the barrel 13 and the release of the forces on the jaws46 cause them no longer to grasp the mandrel so that it passesbackwardly through the plunger and the spring 45 to the rear of the gun.The rivet gun is now ready for another riveting operation.

If, at any time, the operator desires to release the pressure in thegun, it is only necessary for him to move his thumb up and press thebottom end of the valve actuator 17. This causes the plunger 59 to moveto the right (FIG. 9) and open the passage 63. This allows the pressurefluid to flow from the bore 26 through the passage 57 into the bore 56and then through the passage 58 to the reservoir 22. The fact that thepiston 24 is spring-loaded by the spring 25 means that the size of thereservoir changes with the amount of fluid in the various parts of thesystem. The release of pressure from behind the piston 38 allows thespring 46 to retract the piston rod 39 and the rivet handle 16 to thecondition shown in FIG. 8. It should be noted that the combination ofthe plunger 59, the spring 61, the actuator l7, and the spring 66 actsas a relief valve. If the operator attempts to exceed a predeterminedpressure (in the preferred embodiment 3000 psi) in the chamber behindthe piston 24, the pressure makes itself felt on the plunger 62 throughthe passages 57 and 63,. The plunger moves to the right in FIG. 9) andallows fluid to slow into the chamber 56 and through the passage 58 intothe reservoir 23. The excess pressure is thus re-. lieved and any dangerof damage is removed.

An examination of the invention will show a number of advantages. One isthat the pressure brought to. bear on the rivet is completely under thecontrol of the operator, in accordance with the amount he squeezes onthe lever 14. By using long strokes of the lever, of course, heincreases the flow of fluid and the pressure by large amounts. It ispossible by making short strokes to increase the oil pressure and flowin small increments. He would probably want to do this at the time whenthe mandrel is almost ready to break. Because of the tremendous forcesavailable in this hydraulic system, it is possible to handle largerivets, even as large as 3/16 inch. Nevertheless, it is possible torelease the hydraulic pressure built up at any time for safety purposes.It should be noted, incidentally, that the first pumping action of thelever 14 locks the rivet securely in place, so that it is possible towork in overhead locations and to carry the gun from place to place witha rivet securely held in place. The releasing action of the rivet chuckjaws facilitates the removal of the rivet shank or mandrel after theriveting job is finished.

It is obvious that minor changes may be made in the form andconstruction of the invention without departing from the material spiritthereof. It is not, however, desired to confine the invention to theexact form herein shown and described, but it is desired to include allsuch as properly come within the scope claimed.

The invention having been thus described, what is claimed as new anddesired to secure by Letters Patent 1. A rivet gun for use with a hollowrivet having a mandrel, comprising a. a main body having a hand grip anda barrel,

b. a squeeze lever pivotally attached to the main body adjacent the handgrip,

c. a mandrel grip and a rivet anvil mounted on the free end of thebarrel,

(1. a primary piston system carried in the handle and operable by thesqueeze lever,

e. a secondary piston system carried in the barrel and connected to therivet anvil,

f. a reservoir for containing a body of hydraulic fluid,

g. a check valve between the primary piston system and the secondarypiston system.

2. A rivet gun as recited in claim 1, wherein the check valve isarranged to allow fluid flow only from the first piston system to thesecond piston system.

3. A rivet gun as recited in claim 1, wherein a check valve is connectedto allow flow of fluid only from the reservoir to the first pistonsystem.

4. A rivet gun as recited in claim 1, wherein a manually-operable valveis mounted to selectively connect the second piston system to thereservoir.

5. A rivet gun as recited in claim 4, wherein the valve is operated by amovable lever mounted externally of the main body in a position suchthat it can be pressed by the thumb when the hand is wrapped around thegrip.

6. A rivet gun as recited in claim 1, wherein the reservoir isexpandible.

7. A rivet gun as recited in claim 5, wherein the reservoir consists ofa bore in which a piston is slidably mounted, and wherein a coil springlies between one end of the bore and the piston.

8. A rivet gun as recited in claim 1, wherein the second piston systemincludes a power bore extending longitudinally of the barrel, whereinthe first piston system includes a pump bore extending at a right angleto a second piston system bore, and wherein the reservoir includes abore aligned with the second piston system bore.

9. A rivet gun as recited in claim 8, wherein the reservoir bore and thepower bore are separated by a substantial space, and wherein animaginary extension of the pump bore passes through the space.

10. A rivet gun as recited in claim 9, wherein the check valve islocated in the said space to allow fluid flow only from the first pistonsystem to the second piston system, wherein the space includes anothercheck valve connected to allow the flow of fluid only from the reservoirto the first piston system; and wherein the space includes a manuallyoperable valve to selectively connect the second piston system to thereservoir.

11. A rivet gun as recited in claim 1, wherein the squeeze lever isconnected to the first piston assembly by a lever system, wherein thesqueezing of the lever toward the hand grip causes a point in the systemto move the first piston system.

12. A rivet gun as recited in claim 11, wherein the squeeze lever isprovided with a protuberance on the side facing the hand grip, theprotuberance having a pivot point which moves parallel to the axis ofthe pump bore when the squeeze lever is moved toward the handle grip,wherein one end of a first link is pivotally connected to the squeezelever at the said pivot point, wherein one end of a second link ispivotally connected to the handle grip, the other ends of the linksbeing pivotally connected, the first link being formed with an integralbellcrank arm that extends beyond the pivotal connection of the linksand engages a pump piston of the first piston system, and wherein a coilspring concentric with the pump piston is operative to bias the pumppiston and the bellcrank arm in the direction to move the squeeze leveraway from the hand grip.

13. A rivet gun as recited in claim 1, wherein the secondary pistonsystem includes a power bore extending longitudinally of the barrel andhaving a piston with a piston rod extending to the end of the barrel andconnected to the rivet anvil, the anvil having a bore that is

1. A rivet gun for use with a hollow rivet having a mandrel, comprisinga. a main body having a hand grip and a barrel, b. a squeeze leverpivotally attached to the main body adjacent the hand grip, c. a mandrelgrip and a rivet anvil mounted on the free end of the barrel, d. aprimary piston system carried in the handle and operable by the squeezelever, e. a secondary piston system carried in the barrel and connectedto the rivet anvil, f. a reservoir for containing a body of hydraulicfluid, g. a check valve between the primary piston system and thesecondary piston system.
 1. A rivet gun for use with a hollow rivethaving a mandrel, comprising a. a main body having a hand grip and abarrel, b. a squeeze lever pivotally attached to the main body adjacentthe hand grip, c. a mandrel grip and a rivet anvil mounted on the freeend of the barrel, d. a primary piston system carried in the handle andoperable by the squeeze lever, e. a secondary piston system carried inthe barrel and connected to the rivet anvil, f. a reservoir forcontaining a body of hydraulic fluid, g. a check valve between theprimary piston system and the secondary piston system.
 2. A rivet gun asrecited in claim 1, wherein the check valve is arranged to allow fluidflow only from the first piston system to the second piston system.
 3. Arivet gun as recited in claim 1, wherein a check valve is connected toallow flow of fluid only from the reservoir to the first piston system.4. A rivet gun as recited in claim 1, wherein a manually-operable valveis mounted to selectively connect the second piston system to thereservoir.
 5. A rivet gun as recited in claim 4, wherein the valve isoperated by a movable lever mounted externally of the main body in aposition such that it can be pressed by the thumb when the hAnd iswrapped around the grip.
 6. A rivet gun as recited in claim 1, whereinthe reservoir is expandible.
 7. A rivet gun as recited in claim 5,wherein the reservoir consists of a bore in which a piston is slidablymounted, and wherein a coil spring lies between one end of the bore andthe piston.
 8. A rivet gun as recited in claim 1, wherein the secondpiston system includes a power bore extending longitudinally of thebarrel, wherein the first piston system includes a pump bore extendingat a right angle to a second piston system bore, and wherein thereservoir includes a bore aligned with the second piston system bore. 9.A rivet gun as recited in claim 8, wherein the reservoir bore and thepower bore are separated by a substantial space, and wherein animaginary extension of the pump bore passes through the space.
 10. Arivet gun as recited in claim 9, wherein the check valve is located inthe said space to allow fluid flow only from the first piston system tothe second piston system, wherein the space includes another check valveconnected to allow the flow of fluid only from the reservoir to thefirst piston system, and wherein the space includes a manually operablevalve to selectively connect the second piston system to the reservoir.11. A rivet gun as recited in claim 1, wherein the squeeze lever isconnected to the first piston assembly by a lever system, wherein thesqueezing of the lever toward the hand grip causes a point in the systemto move the first piston system.
 12. A rivet gun as recited in claim 11,wherein the squeeze lever is provided with a protuberance on the sidefacing the hand grip, the protuberance having a pivot point which movesparallel to the axis of the pump bore when the squeeze lever is movedtoward the handle grip, wherein one end of a first link is pivotallyconnected to the squeeze lever at the said pivot point, wherein one endof a second link is pivotally connected to the handle grip, the otherends of the links being pivotally connected, the first link being formedwith an integral bellcrank arm that extends beyond the pivotalconnection of the links and engages a pump piston of the first pistonsystem, and wherein a coil spring concentric with the pump piston isoperative to bias the pump piston and the bellcrank arm in the directionto move the squeeze lever away from the hand grip.